BlackTreeIndependent security intelligence

Full vulnerability report · 2026

CVE-2026-33006High confidence

Apache HTTP Server: mod_auth_digest timing attack

Apache Software Foundation · Apache HTTP Server

4.8MediumCVSS 3.1

Recommended action

Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available

Distribution package intelligence

Ubuntu vendor package status

Canonical’s release and source-package findings are shown separately from local repository availability.

1 package state

Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Ubuntu release	Source package	Vendor state	Fixed version	Evidence
Ubuntu 24.04 LTSnoble · standard archive	`apache2`	Vendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree.	`2.4.58-1ubuntu8.12`	Canonical record ↗Source updated 9 Sept 2026

Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current

CVE-2026-33006 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityhttpd: mod_auth_digest: timing attack allows a bypass of digest authentication

30 known affected

The vendor explicitly identifies these products as affected by this CVE.

httpd as a component of Red Hat Enterprise Linux 6
httpd-devel as a component of Red Hat Enterprise Linux 6
httpd-manual as a component of Red Hat Enterprise Linux 6
httpd-tools as a component of Red Hat Enterprise Linux 6
httpd.src as a component of Red Hat Enterprise Linux 6
mod_ssl as a component of Red Hat Enterprise Linux 6
httpd as a component of Red Hat Enterprise Linux 7
httpd-devel as a component of Red Hat Enterprise Linux 7
httpd-manual as a component of Red Hat Enterprise Linux 7
httpd-tools as a component of Red Hat Enterprise Linux 7
httpd.src as a component of Red Hat Enterprise Linux 7
mod_ldap as a component of Red Hat Enterprise Linux 7

Summary: A flaw was found in the mod_auth_digest module of httpd. A remote unauthenticated attacker can bypass digest authentication by measuring timing discrepancies of requests. This issue leads to unauthorized access to resources protected by digest authentication.
Remediation: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current

ENISA EUVD identifier

EUVD-2026-26961

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state: Present in the current official mapping
Known exploitation: Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score: Not supplied in the stored EUVD record
Advisory evidence: No linked advisory details stored yet

Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available

What, why and how

A timing attack against mod_auth_digest in Apache HTTP Server 2.4.66 allows a bypass of Digest authentication by a remote attacker. Users are recommended to upgrade to version 2.4.67, which fixes this issue.

What

Why

Two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Why

How

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path: a network path → Observable Timing Discrepancy → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface: Network
Privileges required: None: unauthenticated exploitation is possible
User interaction: None
Attack complexity: High: exploitation depends on specific conditions
Security boundary: Unchanged: impact remains within the vulnerable component's security authority
Weakness ? CWE means Common Weakness Enumeration: a standard category for the underlying weakness.: CWE-208 ↗
CWE-208: Observable Timing Discrepancy. Two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not.
CVSS vector ? CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CLowConfidentiality impact: A successful attack can cause a limited loss.ILowIntegrity impact: A successful attack can cause a limited loss.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land: No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.

NetworkUnauthenticatedCWE-208

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-26961Official EUVD mapping

0 linked advisory records.

Official EUVD record

BSI · German · WID-SEC-W-2026-1354Apache HTTP Server: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Apache HTTP Server ausnutzen, um erweiterte Privilegien zu erlangen, beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, vertrauliche Informationen offenzulegen oder einen Denial-of-Service-Zustand zu verursachen.

Official advisory

CERT-FR · French · CERTFR-2026-AVI-0608Multiples vulnérabilités dans Microsoft Azure Linux

De multiples vulnérabilités ont été découvertes dans Microsoft Azure Linux. Elles permettent à un attaquant de provoquer un problème de sécurité non spécifié par l'éditeur.

Official advisory

CERT-FR · French · CERTFR-2026-AVI-0530Multiples vulnérabilités dans Apache HTTP Server

De multiples vulnérabilités ont été découvertes dans Apache HTTP Server. Certaines d'entre elles permettent à un attaquant de provoquer une exécution de code arbitraire à distance, une élévation de privilèges et un déni de service à distance.

Official advisory

NCSC-NL · Dutch · NCSC-2026-0134Kwetsbaarheden verholpen in Apache HTTP Server

A timing attack vulnerability in Apache HTTP Server 2.4.66's mod_auth_digest module allows remote attackers to bypass Digest authentication, fixed in version 2.4.67.

Official advisory

Patch and workaround

Operational remediation based on structured source evidence.

Status ? Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.: Patch available
Affected: httpd as a component of Red Hat Enterprise Linux 6; httpd-devel as a component of Red Hat Enterprise Linux 6; httpd-manual as a component of Red Hat Enterprise Linux 6; httpd-tools as a component of Red Hat Enterprise Linux 6; httpd.src as a component of Red Hat Enterprise Linux 6; mod_ssl as a component of Red Hat Enterprise Linux 6; httpd as a component of Red Hat Enterprise Linux 7; httpd-devel as a component of Red Hat Enterprise Linux 7; httpd-manual as a component of Red Hat Enterprise Linux 7; httpd-tools as a component of Red Hat Enterprise Linux 7; httpd.src as a component of Red Hat Enterprise Linux 7; mod_ldap as a component of Red Hat Enterprise Linux 7; mod_proxy_html as a component of Red Hat Enterprise Linux 7; mod_session as a component of Red Hat Enterprise Linux 7; mod_ssl as a component of Red Hat Enterprise Linux 7; httpd-devel (httpd:2.4) as a component of Red Hat Enterprise Linux 8; httpd-filesystem (httpd:2.4) as a component of Red Hat Enterprise Linux 8; httpd-manual (httpd:2.4) as a component of Red Hat Enterprise Linux 8; httpd-tools (httpd:2.4) as a component of Red Hat Enterprise Linux 8; httpd.src (httpd:2.4) as a component of Red Hat Enterprise Linux 8; httpd (httpd:2.4) as a component of Red Hat Enterprise Linux 8; mod_http2.src (httpd:2.4) as a component of Red Hat Enterprise Linux 8; mod_http2 (httpd:2.4) as a component of Red Hat Enterprise Linux 8; mod_ldap (httpd:2.4) as a component of Red Hat Enterprise Linux 8; mod_md.src (httpd:2.4) as a component of Red Hat Enterprise Linux 8; mod_md (httpd:2.4) as a component of Red Hat Enterprise Linux 8; mod_proxy_html (httpd:2.4) as a component of Red Hat Enterprise Linux 8; mod_session (httpd:2.4) as a component of Red Hat Enterprise Linux 8; mod_ssl (httpd:2.4) as a component of Red Hat Enterprise Linux 8; mod_auth_digest.so as a component of Red Hat JBoss Core Services
Fixed: httpd-0:2.4.63-13.el10_2.4.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-0:2.4.63-13.el10_2.4.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-0:2.4.63-13.el10_2.4.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-0:2.4.63-13.el10_2.4.src as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-0:2.4.63-13.el10_2.4.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-core-0:2.4.63-13.el10_2.4.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-core-0:2.4.63-13.el10_2.4.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-core-0:2.4.63-13.el10_2.4.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-core-0:2.4.63-13.el10_2.4.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-core-debuginfo-0:2.4.63-13.el10_2.4.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-core-debuginfo-0:2.4.63-13.el10_2.4.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-core-debuginfo-0:2.4.63-13.el10_2.4.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-core-debuginfo-0:2.4.63-13.el10_2.4.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-debuginfo-0:2.4.63-13.el10_2.4.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-debuginfo-0:2.4.63-13.el10_2.4.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-debuginfo-0:2.4.63-13.el10_2.4.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-debuginfo-0:2.4.63-13.el10_2.4.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-debugsource-0:2.4.63-13.el10_2.4.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-debugsource-0:2.4.63-13.el10_2.4.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-debugsource-0:2.4.63-13.el10_2.4.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-debugsource-0:2.4.63-13.el10_2.4.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-devel-0:2.4.63-13.el10_2.4.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-devel-0:2.4.63-13.el10_2.4.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-devel-0:2.4.63-13.el10_2.4.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-devel-0:2.4.63-13.el10_2.4.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-filesystem-0:2.4.63-13.el10_2.4.noarch as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-manual-0:2.4.63-13.el10_2.4.noarch as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-tools-0:2.4.63-13.el10_2.4.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-tools-0:2.4.63-13.el10_2.4.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); httpd-tools-0:2.4.63-13.el10_2.4.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); and 126 more
Action: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
Workaround: No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.

Evidence and provenance

Published 4 May 2026 · Last source change 4 May 2026, 18:23 UTC · CWE-208 · Observable Timing Discrepancy

CVE recordCVE.org · 5.2

CVSS sourceCISA ADP

EPSS source

The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.

FIRST · tracked since 2026-08-14

European sourceENISA EUVD · EUVD-2026-26961

Product sourceVendor CSAF · Red Hat Product Security

Remediation sourceVendor CSAF · Red Hat Product Security

CWE sourceCNA

NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

2026-05-04CVE published

ENISA EUVD · EUVD-2026-26961↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗

Technical terms and abbreviations used in this report

CVE: Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS: Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS: Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE: Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA: CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP: Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD: National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT: A computer security incident response team that publishes warnings or coordinates incident response.
PoC: Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF: Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL: Living off the land: abuse of legitimate tools or system functions during an attack.

Apache HTTP Server: mod_auth_digest timing attack

National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

EUVD-2026-26961

What, why and how

Exploit reality and attack path

Official authority intelligence

Patch and workaround

Evidence and provenance

National CERT insights
?
CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.